more expressive CUDA error macro. instead of 'cuda error = 2', now we get 'cuda error = 2 (out of memory)'
writing CUDA errors to LOG(FATAL) instead of stderr
revert Makefile
using 'cout' instead of 'printf' style syntax for writing GPU errors to GLOG.
Merge pull request #193 from forresti/gpu_debug_macros

report expressive CUDA errors instead of bare error numbers.